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A. M. Santos,I. P. Aquino,F. Cotting,I. V. Aoki,H. G. de Melo,V. R. Capelossi 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.6
This work aims to investigate the possible use of the palm kernel cake powder (Elaeis guineensis Jacq.) as corrosioninhibitor for ASTM 1020 carbon steel in acidic media (0.5 mol L−1 HCl). The investigation was carried out using electrochemicalimpedance spectroscopy (EIS), polarization curves, gravimetric technique and scanning vibrating electrode technique(SVET). Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed aschemical and surface characterization techniques, respectively. The results of the EIS and gravimetric tests showed that thesubstance acts as an effective corrosion inhibitor and inhibition efficiency (IE) increases according with the increase of thecorrosion inhibitor concentration in the aggressive medium. The highest IE of 87% was obtained for the highest corrosioninhibitor concentration used (1.77 g/L). The polarization curves revealed a mixed inhibitor. The adsorption of the studiedinhibitor on carbon steel surface obeyed Langmuir isotherm. The SVET measurements did not reveal anodic or cathodicactivities in the substrate surface in the presence of the inhibitor, revealing that the corrosion inhibitor was able to block bothreactions. FTIR analyses identified in the powder the presence of hydroxyl group, aromatic rings, nitrogen and oxygen in suchgroups as amines and oleaginous acid, which can be responsible for the inhibitory properties of the whole material. SEManalyses showed that the corrosion process was retarded when the inhibitor was added to electrolyte. The results indicatethat the powder of palm kernel cake is promising for use as corrosion inhibition purpose for carbon steel in acidic media.
Sabrine Zghal,Ilyes Jedidi,Marc Cretin,Sophie Cerneaux,Didier Cot,Serge Lagerge,Stefano Deabate,Makki Abdelmouleh 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.8
The highest total organic carbon (TOC) and color removal efficiency of Acid Orange 7 (0.1 mM initialconcentration) on graphite carbon/carbon nanotubes electrodes (KS44/CNT) reached more than 98% in three hours ofElectro-Fenton (EF) treatment under optimal conditions (pH=3 and I=20 mA), compared to carbon graphite electrodedeveloped without carbon nanotubes (KS44-0). The apparent kinetic constants of degradation were 0.17 and0.12 min1 for the KS44-(20)/CNT and KS44-0, respectively. The long-term stability and system durability were attributedto the graphite carbon/CNT electrodes due to continuous operating treatment that allowed processing efficiency andreusability without any decrease of the catalytic activity in time after five cycles of use. Regardless of the medium, superiordecolorization and TOC removal efficiency were obtained for electrodes (KS44-(20)/CNT) containing 20 wt% offerrocene powder as catalyst for CNTs’ growth and iron nanoparticle establishment. Furthermore, the presence ofCNTs and iron particles as precursors enhanced drastically the electrochemical and physical properties of the electrodesynthesized in a one-step process. The results confirmed that carbon electrodes behave as multifunctional materials actingboth as adsorbent and active cathode in the electro-Fenton process for the destruction and total mineralization ofAcid Orange 7 (AO7) as a model for organic contaminated wastewater.
Gustavo Tomas Galo,Andréia de A. Morandim‑Giannetti,Fernando Cotting,Idalina Vieira Aoki,Isabella Pacifico Aquino 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9
The capacity of the Allium cepa L. extract from peel (ACP) and bulb (ACB) as a natural corrosion inhibitor for carbon steelwas evaluated. The corrosion characterization was performed by a gravimetric test, showing an inhibitor efficiency of 60%(ACP) and 67% (ACB). Electrochemical tests indicated higher corrosion resistance for carbon steel in the presence of theextracts, and the SEM images of steel samples confirm the results. These extracts were analyzed by the DPPH (2,2-diphenyl-1-picrylhydrazyl) method, confirming the antioxidant activity. The chemical characterization of the extracts by FTIR measurementsrevealed the presence of phenolic compounds with antioxidant capacity.
Israel Parra-Ortega,Diana Guadalupe Alcara-Ramirez,Alma Angelica Ronzon-Ronzon,Fermin Elias-Garcia,Jose Agustin Mata-Chapol,Alejandro Daniel Cervantes-Cot,Briceida Lopez-Martinez,Miguel Angel Villasis 한국영양학회 2021 Nutrition Research and Practice Vol.15 No.S
BACKGROUND/OBJECTIVES: Considering the high number of deaths from coronavirus disease 2019 (COVID-19) in Latin American countries, together with multiple factors that increase the prevalence of vitamin D deficiency, we aimed to determine 25-hydroxyvitamin D (25[OH]D) levels and its association with mortality in patients with critical COVID-19. SUBJECTS/METHODS: This was a prospective observational study including adult patients with critical COVID-19. Data, including clinical characteristics and 25(OH)D levels measured at the time of intensive care unit admission, were collected. All patients were followed until hospital discharge or in-hospital death. The patients were divided into those surviving and deceased patient groups, and univariate and multivariate logistic regression analyses were performed to determine independent predictors of in hospital mortality. RESULTS: The entire cohort comprised 94 patients with critical COVID-19 (males, 59.6%; median age, 61.5 years). The median 25(OH)D level was 12.7 ng/mL, and 15 (16%) and 79 (84%) patients had vitamin D insufficiency and vitamin D deficiency, respectively. The median serum 25(OH)D level was significantly lower in deceased patients compared with surviving (12.1 vs. 18.7 ng/mL, P < 0.001). Vitamin D deficiency was present in 100% of the deceased patients. Multivariate logistic regression analysis revealed that age, body mass index, other risk factors, and 25(OH)D level were independent predictors of mortality. CONCLUSIONS: Vitamin D deficiency was present in 84% of critical COVID-19 patients. Serum 25(OH)D was independently associated with mortality in critical patients with COVID-19.